Substituted methylamine compounds, including pyridylmethylamine compounds such as 2-chloro-5-pyridylmethylamine, are useful as intermediates for the production of agricultural chemicals and medicines.
Conventionally, known processes for producing pyridylmethylamine compounds include a process in which 2-chloro-5-chloromethylpyridine is reacted with potassium phthalimide to obtain N-(2-chloro-5-pyridylmethyl)phthalimide, which is subsequently reacted with hydrazine (see Patent Document 1), a process in which 2-chloro-5-(chloromethyl)pyridine is reacted with hexamethylenetetramine to obtain 2-chloro-5-pyridylmethylhexamethylenetetraammonium chloride, and a hydrolysis is subsequently performed in the presence of a lower alcohol and a mineral acid (see Patent Document 2), and a process in which 2-chloro-5-pyridylmethylhexamethylenetetraammonium chloride is hydrolyzed using water or alkaline water to generate N-methylidene-2-chloro-5-pyridylmethylamine, which is subsequently isolated and then hydrolyzed in an acid (see Patent Document 3).
However, none of these production processes can be claimed to be entirely satisfactory from an industrial perspective. Namely, the first process requires the use of the comparatively expensive potassium phthalimide as a raw material, meaning the process is undesirable from an economic perspective. Further, because an operation is required to remove phthalazine from the hydrazine reaction mixture, the post-processing operation tends to be complex. In the case of the second process, the amount of solvent used in the reaction is large, and a large amount of comparatively expensive hexamethylenetetramine must also be used, and therefore the process is undesirable from an economic perspective. Further, in this process, because the generated 2-chloro-5-pyridylmethylhexamethylenetetraammonium chloride must be first isolated, before being subjected to hydrolysis, a problem arises in that the operation is overly complex. In the third process, a problem arises in that the isolated N-methylidene-2-chloro-5-pyridinemethylamine is unstable and difficult to handle.
[Patent Document 1]    (West) German Pat. No. 3,727,126
[Patent Document 2]    Japanese Unexamined Patent Application, First Publication No. Hei 3-271273
[Patent Document 3]    Japanese Unexamined Patent Application, First Publication No. Hei 8-295670